WOODWARD SST-ESR2-CLX Replacement/Upgrade for SST Series

Product Overview

WOODWARD SST-ESR2-CLX Replacement/Upgrade Solution for SST Series: Seamless Transition from Legacy EtherNet/IP TCP Interface Modules

The WOODWARD SST-ESR2-CLX is a high-performance EtherNet/IP TCP Interface Module engineered for direct integration with Allen-Bradley ControlLogix (CLX) platforms. As legacy SST Series communication modules reach end-of-life or become increasingly difficult to source, plant engineers and system integrators face mounting pressure to maintain network uptime without triggering a full control system overhaul. The SST-ESR2-CLX is purpose-built to address exactly this challenge — delivering a drop-in compatible upgrade path that preserves existing wiring infrastructure, communication protocols, and rack geometry while eliminating the risks associated with running obsolete hardware.

Whether you are migrating from an earlier SST-ESR1 interface card, replacing a failed communication bridge in a multi-rack ControlLogix chassis, or consolidating a distributed I/O network onto a unified EtherNet/IP backbone, the SST-ESR2-CLX provides the protocol translation, deterministic scan cycle, and dual-port Ethernet topology support required for modern industrial environments. Its compatibility with the standard 1756-series backplane means it slots directly into existing ControlLogix racks alongside modules such as the 1756-EN2T EtherNet/IP bridge and 1756-L71 controller without requiring mechanical modification or additional mounting hardware.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful migration to the SST-ESR2-CLX rarely involves a single module swap in isolation. In practice, upgrading the EtherNet/IP TCP interface is the catalyst for a broader system modernization that touches multiple layers of the control architecture. During the retrofit process, engineers typically evaluate the health and compatibility of adjacent components to avoid creating new single points of failure.

On the controller side, the SST-ESR2-CLX is validated for use with the Allen-Bradley 1756-L71 and 1756-L73 ControlLogix processors. If the existing controller is an older 1756-L55 or 1756-L61 running Logix firmware below v20, a coordinated firmware upgrade or controller replacement is recommended to unlock the full DLR ring topology features of the SST-ESR2-CLX. The module’s EDS file integrates cleanly into Studio 5000 projects, allowing existing Add-On Instructions (AOIs) and tag structures to be preserved with minimal rework.

For distributed I/O networks, the SST-ESR2-CLX serves as the EtherNet/IP scanner that manages remote 1734 POINT I/O and 1769 CompactLogix I/O adapter nodes. When replacing a failed legacy bridge, it is advisable to simultaneously inspect the 1734-AENT or 1734-AENTR EtherNet/IP adapter modules at each remote I/O drop, as these components share the same network segment and are subject to similar aging cycles. Replacing worn terminal bases or I/O modules at this stage avoids repeat shutdowns.

Power integrity is a critical factor in any retrofit. The 1756-series chassis relies on the 1756-PA72 or 1756-PB72 power supply module to deliver stable backplane voltage. Before commissioning the SST-ESR2-CLX, verify that the chassis power supply is within its rated load capacity, particularly if additional communication modules such as a 1756-DHRIO Data Highway Plus / Remote I/O bridge or a 1756-CN2 ControlNet interface are co-installed in the same rack. Overloaded power supplies are a common root cause of intermittent communication faults that are misdiagnosed as module failures.

For facilities that operate legacy DeviceNet or Profibus segments alongside the EtherNet/IP network, the SST-ESR2-CLX can coexist in the same chassis with a 1756-DNB DeviceNet scanner or a third-party Profibus DP master module. This multi-protocol architecture is common in brownfield plants where older variable frequency drives, motor starters, and valve positioners have not yet been migrated to EtherNet/IP. Signal isolation between the legacy fieldbus and the new EtherNet/IP segment can be maintained using DIN-rail-mounted signal isolators or protocol converters installed in the same control cabinet.

Programming cable access is another practical consideration during commissioning. The 1756-USB or 1747-UIC USB-to-DH+ interface cable is typically required for initial controller connection when the EtherNet/IP path is being reconfigured. Having this cable on-site before the maintenance window begins eliminates a common source of commissioning delay. Similarly, a laptop pre-loaded with the correct version of Studio 5000 and the SST-ESR2-CLX EDS file should be prepared in advance.

Retrofit Guidance FAQ

Q: Can the SST-ESR2-CLX replace the SST-ESR1-CLX without modifying the existing Ethernet wiring?
A: Yes. Both modules use standard RJ-45 connectors and operate on the same EtherNet/IP CIP protocol stack. The existing Cat5e or Cat6 patch cables connect directly to the SST-ESR2-CLX without modification. The dual-port design of the ESR2 allows you to optionally implement a Device Level Ring topology for improved network redundancy, but this is not required for a basic replacement.

Q: Do I need to rewrite my Studio 5000 program after installing the SST-ESR2-CLX?
A: In most cases, no. The SST-ESR2-CLX uses a standard EDS file that registers the module in the Studio 5000 I/O tree. If your existing program references the legacy module by its EDS-defined parameters, you will need to delete the old module entry and add the SST-ESR2-CLX using its EDS file. Existing tag names, AOIs, and ladder logic rungs that reference those tags remain unchanged. A full program rewrite is not required.

Q: Is the SST-ESR2-CLX compatible with older ControlLogix firmware versions?
A: The SST-ESR2-CLX is compatible with ControlLogix firmware v16 and above. For DLR ring topology support, firmware v20 or higher is recommended. If your controller is running firmware below v16, a firmware upgrade should be performed before installing the module. TOPNLMS can advise on firmware compatibility based on your specific controller model and revision.

Q: How much physical space does the SST-ESR2-CLX require in the control cabinet?
A: The SST-ESR2-CLX occupies a single 1756-series backplane slot — identical to the legacy SST-ESR1-CLX. No additional DIN rail space, external power supply, or cabinet modification is required. The module’s Ethernet ports face the front of the chassis, maintaining the same cable routing as the previous module.

Q: What communication protocols does the SST-ESR2-CLX support?
A: The SST-ESR2-CLX supports EtherNet/IP (CIP), TCP/IP, and UDP. It functions as an EtherNet/IP scanner (Class 1 and Class 3 connections) and supports explicit messaging for configuration and diagnostics. It does not natively support Modbus TCP or Profinet; protocol conversion for those networks requires an external gateway device.

Q: Can the SST-ESR2-CLX be used in a redundant ControlLogix system?
A: Yes, the SST-ESR2-CLX is compatible with ControlLogix redundancy configurations when paired with the appropriate redundancy module (1756-RM or 1756-RM2). Consult the Rockwell Automation redundancy compatibility matrix and the WOODWARD SST-ESR2-CLX installation manual to confirm the specific firmware and chassis slot requirements for your redundancy configuration.

Warranty Assurance

Every WOODWARD SST-ESR2-CLX unit supplied by TOPNLMS is covered by a 12-month warranty from the date of shipment. Before dispatch, each module undergoes a multi-point outgoing inspection that includes visual examination, connector integrity verification, and functional communication testing to confirm the module initializes correctly and responds to EtherNet/IP configuration commands.

In the event of a confirmed hardware defect within the warranty period, TOPNLMS will arrange a replacement unit at no additional cost. Our after-sales response target is one business day for warranty claims submitted with a fault description and photographic evidence. For urgent production-down situations, expedited replacement shipping is available upon request.

TOPNLMS maintains a standing inventory of SST-ESR2-CLX modules to support rapid fulfillment for both planned maintenance schedules and emergency breakdowns. Orders placed before 14:00 CST on business days are typically processed for same-day dispatch. International shipments are supported via DHL Express, FedEx International Priority, and UPS Worldwide Expedited, with full tracking provided at the time of shipment.

For procurement teams requiring documentation, TOPNLMS can provide a commercial invoice, packing list, certificate of conformance, and test report upon request. These documents support customs clearance, internal audit requirements, and asset management records.